1. Field of the Invention
The present invention relates to a units count control method for automatically controlling the number of units to be operated out of fluid heating units installed in a plurality, such as hot water boilers, thermal liquid boilers, heat exchangers, and absorption type refrigerators, in response to the load condition.
2. Description of the Prior Art
As is well known, there have been put into practical use multi-unit installation systems of hot water boilers in which a plurality of hot water boilers are installed in parallel and the number of units to be operated out of these hot water boilers is automatically controlled in response to the load condition. Such a multi-unit installation system of hot water boilers is capable of making each hot water boiler operated at higher efficiency, as compared with the case in which a single unit of large-capacity hot water boiler is installed. Thus, the multi-unit installation system has advantages of producing notable effects on energy saving and being superior in responsivity to variations in the load.
However, in recent years, the multi-unit installation system of hot water boilers has been receiving growing demand for higher levels of responsivity to load variations as well as for prevention of useless starts and stops (i.e., supplying hot water of stable temperature).